Does the Caramel Coloring in Colas Cause Cancer?

Lab tests commissioned by a consumer group find that popular colas — including Coke and Pepsi — carry a caramel-coloring chemical that causes cancer in lab animals.

The chemical, 4-methylimidazole or 4-MI, comes from the sodas’ caramel coloring. That color is made not from natural caramel but via a chemical process involving ammonia. While toxicology studies show that 4-MI can cause cancer in lab animals, it’s not clear whether it’s a human carcinogen — or whether the amounts detected in sodas pose any kind of a threat.

The Center for Science in the Public Interest (CSPI) in February 2011 petitioned the FDA to ban this kind of caramel coloring. It also wanted the cosmetic additive renamed “chemically modified caramel coloring” or “ammonia-sulfite process caramel coloring.”

The CSPI-commissioned tests detected 4-MI in regular and diet Coca-Cola and Pepsi products — in millionths of a gram per 12-ounce can. CSPI notes that these quantities are several times higher than a controversial benchmark set by the state of California’s Office of Environmental Health Hazard Assessment. While the CSPI suggests that 4-MI is causing cancer in thousands of Americans who drink a lot of cola, the FDA says few people should worry.

“A consumer would have to consume well over a thousand cans of soda a day to reach the doses administered in the studies that have shown links to cancer in rodents,” the FDA tells WebMD. And while it believes 4-MI is a threat, the CSPI says it’s less of a threat than the obesity-promoting high-fructose corn syrup in soft drinks.